In the related art, there is a technology in which a hierarchical storage is formed by multiple storages that are different in access performance and in which data is moved between the storages. Furthermore, there is a technology in which a storage of which the access performance is improved more than a storage device described above is formed by using the storage device and a cache memory. As the related art, for example, there is a technology in which, in a case where whether or not to access pieces of data in successive sectors of a hard disk drive (HDD), of which the number is equal to or greater than a given number, is determined in response to a request from a host for access to a HDD, the storage device is not used as a cache. Furthermore, there is a technology in which each of the IO requests from applications is compared with a cache map that is able to be configured, each of the IO requests is processed based on the cache map that is able to be configured, and caching is selectively performed on each of the IO requests according to a caching determination that is granted.
As an example of the related art, Japanese Laid-open Patent Publication No. 2013-77161 and Japanese National Publication of International Patent Application No. 2013-511091 are known.